Ted Kennedy had spent the evening of July 18, 1969, attending a party on Chappaquiddick Island with several friends and campaign aides. Shortly before midnight, he offered to drive Mary Jo Kopechne back to her hotel. Instead, he turned down an unlit dirt road leading to Dike Bridge, unfamiliar and treacherous at night.

The car veered off the wooden bridge and plunged into the water below. Kennedy managed to escape, swimming to shore in shock. Mary Jo remained trapped inside. Disoriented and fearful, Kennedy left the scene, setting off a chain of decisions that would define the rest of his life.